Near the end of the tutorial you will be introduced to the unit production page.
Depending on which buildings you have already constructed you will see here how many of each unit type you can produce simultaneously. Simply enter the number of troops you would like to produce and start with their recruitment. Once they have been completed, you will see the new units in the aforementioned Unit production overview.
With this introduction to MonstersArmy we were naturally only able to give you a minute glimpse of the manifold possibilities the game offers. Only the more vital game aspects were covered in the overview.
For more details, tactical tips or answers to any questions you may have, we suggest you venture into the official game forum http://board.monstersarmy.com/
to contact the many experienced players there. You can of course als use the forum to search for alliance members or to brag about your most glorious victories. You should definitely take a look at the game and become a member of the MonstersArmy community.